Classifications

• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
  • C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
  • C02F1/56—Macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F11/00—Treatment of sludge; Devices therefor
  • C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
  • C02F11/14—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents
  • C02F11/147—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents using organic substances
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F1/00—Treatment of water, waste water, or sewage
  • C02F1/68—Treatment of water, waste water, or sewage by addition of specified substances, e.g. trace elements, for ameliorating potable water
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
  • C02F2103/10—Nature of the water, waste water, sewage or sludge to be treated from quarries or from mining activities
• • C—CHEMISTRY; METALLURGY
  • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
  • C02F9/00—Multistage treatment of water, waste water or sewage

Definitions

• This invention concerns a method for treating mineral sludge by using polymers. Among other uses, it can be applied to the treatment of effluents from the mining or mineral industry, including the treatment of bituminous sand residues. It can also be applied to dredging processes or public works operations which produce large amounts of mineral sludge. In both cases, the objective is to dry and solidify the sludge above ground.
• This super-flocculation (over-flocculation) in the piping enables the sludge to form a flow slope so it can be stored above ground rather than in a holding tank.
• the water released from the over-flocculated sludge was recycled in a peripheral trench for re-pumping. It was also demonstrated that a layer of crushed rock placed under the storage area enabled the interstitial water to drain, sharply reducing drying time. Likewise, adding the flocculating agent in a plurality of points improved its effectiveness and partially reduced consumption.
• the first embodiments of super-flocculation were developed in Japan and France. We can notably mention the dredging of the container ship port at Port de Bouc and Fos sur Mer.
• the method applied consisted, in a first step, in conditioning the sludge (either from a phosphate washing plant or from dredging lagoons where it had been stored) with flocculating agents in a settling tank or in a settling tank and then a thickener. The thickened sludge was then pumped to an above-ground area, where it was disposed after adding an additional amount of an organic flocculating agent in a solution at one or more points in the piping.
• bituminous sand residues have recently become an issue in Canada (Athabaska).
• bitumen heavy oil
• large quantities of sand and clay have to be extracted to retrieve the oil by steam heating or other similar processes.
• the sands are then separated by cycloning and the clays, after a thickening stage, are stored in huge basins where they cannot be dried.
• the invention solves all the difficulties mentioned above.
• the purpose of this invention is therefore to develop a method and polymers for treating effluents from the mining or mineral industry for subsequent drying and solidification above ground, so that the storage site becomes usable again.
• the subject of the invention is therefore firstly a method for treating sludge from the mining or mineral industry, according to which the sludge is placed in contact with a flocculating agent before being spread above ground.
• the method is characterized in that the flocculating agent is a water-soluble organic polymer with a molecular weight between 5,000,000 and 25,000,000 g/mol and which presents an anionicity of between 10 and 40 mol % and comprises:
• the polymer is branched.
• a branched polymer is a polymer that has branches or groups on the main chain, generally laid out on the same plane. Branching could preferably be performed during (or possibly after) polymerization, in the presence of a branching/crosslinking agent and possibly a transfer agent.
• branching agents methylenebisacrylamide (MBA), ethylene glycol diacrylate, polyethylene glycol dimethacrylate, diacrylamide, cyanomethyl acrylate, vinyloxyethyl acrylate or methacrylate, triallylamine, formaldehyde, glyoxal, compounds of the glycidyl ether type such as ethylene glycol diglycidyl ether, or epoxies or any other method known to the person skilled in the art, producing crosslinking.
• MCA methylenebisacrylamide
• ethylene glycol diacrylate polyethylene glycol dimethacrylate
• diacrylamide diacrylamide
• cyanomethyl acrylate vinyloxyethyl acrylate or methacrylate
• triallylamine formaldehyde
• glyoxal compounds of the glycidyl ether type such as ethylene glycol diglycidyl ether, or epoxies or any other method known to the person skilled in the art, producing crosslink
• the flocculating agent is added to the sludge at a concentration between 50 and 1500 g per ton of solids, depending on the nature and the composition of the sludge to be treated.
• contact time between the sludge and the flocculating agent is between 1 and 10 minutes, advantageously between 2 and 5 minutes.
• the sludge flow angle at the time of spreading is preferably between 8 and 20% (i.e. difference of level over 100 meters horizontally).
• the invention includes other embodiments.
• the sludgy effluents also called slurry, sludge, pulp
• the sludgy effluents come from dredging processes, public works operations, effluents from ore extraction (coal, alumina, platinum, phosphate, iron, diamonds, gold, copper, etc.), bituminous sand or any other type of aqueous sludge made up of clay or silt.
• the flocculating agents used include all types of water-soluble anionic organic polymers, including amphoteric polymers.
• the polymer used comprises:
• the solution is first cooled, neutralized with soda and then degassed under a nitrogen flow. Polymerization is then initiated using a redox couple (initiator). The gel obtained after polymerization is then grinded and dried in a drying oven to obtain a powder.
• Clay sludge from a waste storage lagoon are transported by dredging at a pumping rate of 250 m 3 /h with an average concentration of 400 to 500 g/l.
• the sludge is transported approximately 2 km and treated with an anionic flocculating agent (AM/AANa 70/30, molecular weight: 18 million g/mol) with a concentration of 5 g/L.
• AM/AANa 70/30, molecular weight: 18 million g/mol anionic flocculating agent
• This solution is fed into the sludge feed pipe at one point or two points in quantities ranging from 500 g to 1,500 g per ton of solids.
• the sludge at the pumping tube outlet has a colloidal structure, a soft appearance and a very low flow slope (approximately 1% after pumping is stopped). Furthermore, we can observe that there is very little water runoff from the sludge. From the viewpoint of structure and hardness, very little difference can be seen between the pumped sludge and the flocculated sludge.
• the flocculating solution is added into the sludge feed pipe at one or two points at a short or medium distance (200 m) from the pouring point in a quantity ranging from 500 g to 1,500 g per ton of solids.
• the very clear runoff water containing 3-5% oil is released from the sludge and immediately after pumping stops has a concentration of 650 g/L. After 15 days at an average outside temperature of 10° C., surface cracking is such that it has the appearance of rubble that can be handled to form piles.

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• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Hydrology & Water Resources (AREA)
• Engineering & Computer Science (AREA)
• Environmental & Geological Engineering (AREA)
• Water Supply & Treatment (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Separation Of Suspended Particles By Flocculating Agents (AREA)
• Treatment Of Sludge (AREA)

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Citations (13)

• 2008
  • 2008-10-23 FR FR0857212A patent/FR2937635B1/fr not_active Expired - Fee Related
• 2009
  • 2009-10-14 CA CA2682542A patent/CA2682542C/fr active Active
  • 2009-10-20 US US12/588,570 patent/US8562838B2/en not_active Expired - Fee Related

Patent Citations (14)

Non-Patent Citations (1)

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